Stabilized water indicating paste composition

ABSTRACT

A visual indicating paste composition for producing a detectable color change upon contact with an aqueous solution comprising an indicator dye capable of changing color in the pH range between about 7 and about 11, an inorganic base in the form of a caustic powder dispersed in a liquid carrier capable of absorbing water which is not rapidly leached by water or hydrocarbon, and a minor amount of a boron-containing compound, is provided. When applied to a measuring probe, the paste composition is particularly adapted for detecting the water level in the bottom of tanks and delivery systems containing gasoline, and especially gasoline containing oxygenated blending components, by producing a clear detectable color change without bleeding or run-off upon contact with an aqueous solution. The paste composition exhibits long shelf life and improved water tolerance.

This is a division of application Ser. No. 507,856 filed June 27, 1983,now U.S. Pat. No. 4,578,357, issued on Mar. 25, 1986.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to novel stabilized visual indicatingpaste compositions and to the utilization of the same to detect thepresence, and particularly the level, of aqueous solutions when admixedwith hydrocarbons, such as gasoline, oil or other fuel and petroleumfractions. More particularly, the present invention is concerned withstabilized visual indicating paste compositions which are capable ofundergoing a change in color upon contact with aqueous solutions whichmay be present in minor amounts, generally as a separate phase, inhydrocarbon storage tanks, delivery vehicles, distribution systems, andthe like. The compositions of the invention are particularly adapted foruse in determining the water level in the bottom of gasoline storage andtransportation tanks to determine the amount of water resting in thetank partially filled with the hydrocarbon, and when the water containsoxygenated blending components, such as ethers and alcohols.

2. Description of the Prior Art

Paste compositions detecting the level or presence of water have beendisclosed in the prior art. In U.S. Pat. No. 2,520,993, there isdisclosed a composition illustrative of such pastes comprising a watersoluble cobalt thiocyanate and a finely dispersed filler material havinga color other than that of the thiocyanate. Polish Pat. No. 94,388discloses a paste, which changes color from blue to white or light pinkupon contact with water, obtained by blending ammonium thiocyanate withcobalt chloride, an aromatic amine, glycerol, paraffinic oil and groundchalk. Austrian Patent 360,961 discloses a self-adhesive indicator pasteuseful for detecting pH, nitrate and iron, coated on a polystyrenecarrier, which is prepared by impregnating the carrier material with oneor more indicator solutions containing Ethyl Red, bromxylenol blue, andacetone.

Pastes for detecting the level of water in hydrocarbon storage tanks,such as gasoline tanks employed at service stations, have beencommercially available. In use, such pastes undergo a color change aftercontacting with water. However, certain of these commercially availablepastes are deficient in one or more characteristics, for example, infailing to exhibit a sharp and distinct color change, or alternatively,in having high solubility in the water or hydrocarbon phases, orcomparatively short shelf life, or in exhibiting high hygroscopicity. Aparticular difficulty has been encountered with conventional waterindicating pastes when attempts have been made to obtain accuratereadings of the water level in tanks and delivery systems forhydrocarbons, such as gasoline, wherein the water contains oxygenatedgasoline blending components leached from the gasoline, which componentspreclude the obtainment of a sharp and distinct color change or causebleed or run off the measuring probe coated with the paste whencontacted with such oxygen-containing aqueous solutions.

In U.S. application Ser. Pat. No. 490,744 filed May 2, 1983, of F. W.Melpolder and J. G. Victor entitled "Composition and Probe for Detectionof Water," there is disclosed a visual indicating paste composition forproducing a detectable color change upon contact with an aqueoussolution comprising a water soluble indicator dye capable of changingcolor in the pH range between about 7 and 11 and an insoluble, inorganicbase in the form of a caustic powder dispersed in a liquid carriercapable of absorbing water but which is not rapidly leached by water orhydrocarbon. It has been found, however, that the water indicating pastedisclosed in said application, may turn color during storage due to theintroduction of trace quantities of water originating from one or moresources. Hence, water may penetrate the paste should humid conditionsexist during manufacture or storage of the paste or water may beabsorbed by the paste while opening the container during eachapplication of the paste by the user. In addition, water may beintroduced with the ingrediants, such as liquid carriers, employed informulation of the paste.

OBJECTS AND SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide astabilized visual indicating paste which exhibits long shelf life andimproved water tolerance, while at the same time being characterized bylow solubility in aqueous solutions and hydrocarbons, and good adhesionto substrates to which it is applied.

Another object of the invention is to provide a visual indicating pastefor producing a detectable color change upon contact with aqueoussolutions without bleeding and which will react rapidly with water butnot with any other oxygenated component which may be contained therein,or with the hydrocarbon with which the water is admixed.

Still another object is to provide a probe having coated thereon astabilized visual indicating composition which is useful for locatingthe water level of aqueous solutions containing oxygenated blendingcomponents in the bottom of tanks and delivery systems containinghydrocarbons such as gasoline, and particularly for indicating sharp anddistinct color changes without bleeding or running off the probe.

These and other objects, features and advantages of the invention willbe in part obvious and apparent from the specification.

It has now been discovered, after testing a number of combinations ofmaterials, that paste compositions comprised of (i) a dye capable ofchanging color in the pH range between about 7 and about 11 and (ii)certain inorganic bases dispersed in a liquid carrier, exhibitconsiderable improvement in shelf life and water tolerance when suchpaste compositions contain a minor amount of certain boric acid estersor related organic compounds in which the boron is attached to oxygen,as compared with pastes devoid of such boron compounds and/or withcommercially available pastes. Further, the paste compositions of theinvention produce a sharp and distinct color change, without bleeding,upon contact with water, and particularly, with aqueous solutionscontaining oxygen-containing organic compounds, such as lower alkanolsand ethers. As is noted in the aforementioned application Ser. Pat. No.490,744, the disclosure of which is hereby incorporated by reference,water or aqueous solutions promote the caustic powder-indicator dyecolor reaction of the paste compositions dissolved therein. It wasindeed surprising to discover that certain esters of boric acid andrelated organic compounds in which boron is attached to oxygen arecapable of acting as a water scavanger in such compositions, therebychemically reacting with water or aqueous solutions prior to the causticpowder-indicator dye color reaction, especially since attempts to employother added organic compounds including acids, anhydrides, salts,oxides, molecular sieve adsorbents and active metal compounds were allunsuccessful. These compounds failed due to the reaction being eithertoo slow or too active, thereby rendering the caustic powder of theaforementioned paste compositions impotent. Specific examples offailures included adipic acid, stearic acid, maleic anhydride, boricacid, calcium chloride, aluminum isoproproxide and aluminum sulfate.

In accordance with the present invention, any ester of boric acid oranhydride, ortho or meta, or related organic compound in which boron isattached to oxygen, and capable of being hydrolyzed upon contact withwater to yield boric acid or a salt thereof, are employable asstabilizers in the paste compositions of the present invention. Anadditional required characteristic of the boron compounds employableherein is that they be fully miscible with or soluble in the liquidcarrier of the paste composition. Any ester, or partial ester, of boricacid, also termed alkoxy- and aryloxy boranes, may be convenientlyemployed as an ingredient of the composition of the present invention.In general, these boron esters conform to the general formula: ##STR1##wherein R taken singly may be the same or different, and may be: (a)alkyl, primary or secondary, substituted or unsubstituted, having fromone to twenty-two carbon atoms, such as ethyl, propyl, hexyl, hexadecyl,stearyl, eicosyl and the like, or

(b) aryl, substituted or unsubstituted, such as tolyl, phenyl, xylyl andthe like;

(c) aralkyl, substituted or unsubstituted, having from seven to twentycarbon atoms such as benzyl, phenethyl, 4-methylbenzyl and the like; or

(d) hydrogen;

with the proviso that at least one R be alkyl, aryl or aralkyl. Straightchain trialkyl borates are preferred. Illustrative alkyl boratesemployable in the paste compositions of the invention include triethylborate, tripropyl borate, tri-isopropyl borate, trimethylene borate,tri-n-butyl borate, tri-n-hexyl borate, and tri stearyl borate. Tertiaryalkyl borates, it has been found, do not provide the stability of theprimary and secondary alkyl borates.

Other boron compounds employable in the compositions of the presentinvention include acyloxyboranes conforming to the general formulae:##STR2## wherein R is as defined above. Typical examples ofacyloxyboranes employable include acetyloxyborane, hexaoctonoyloxyborane, and oxy-bis(boron acetate) and the like. Another class ofboron-containing compounds employable in the compositions of theinvention are alkoxyhaloboranes represented by the structures:

    ROBX.sub.2                                                 (IV)

    and (RO).sub.2 BX                                          (V)

wherein R is a primary or secondary alkyl group as above defined and Xis a halogen atom such as chlorine and fluorine. Illustrativealkoxyhaloboranes include methyloxydichloroborane,octyloxychlorofluoroborane, and monochlorohexylborate.Polyhydroxylborates such as ethylene glycol biborate, propylene glycolbiborate and catechol biborate serve as an example of still anotherclass of boron compounds suitable as constituents of the compositions ofthe invention.

The boron compound is employed in the paste composition in an amountsufficient to provide the desired stabilization or inhibition tomoisture. In general, the boron compound stabilizer is present in thecomposition of the invention in a concentration ranging from about 0.05to about 5, preferably between about 0.5 and about 3 percent, by weightof the composition.

The stabilized visual indicating paste compositions of the presentinvention turn color, generally within about 30 seconds or less, andnormally within about 5 to 15 seconds or less, depending upon theindicator dye employed, upon contact with water or an aqueous liquid,i.e., a liquid having aqueous properties, such as water-containing anoxygenated hydrocarbon, including: lower alcohols, illustrativelymethanol, ethanol, tertiary butyl alcohol, secondary butyl alcohol andmixtures thereof; lower polyols such as alkylene glycols, and lowerketones such as acetone and methyl tertiary butyl ether, and the like.The term "aqueous liquid" is employed herein to designate suchsubstances having chemical characteristics similar to those of water, asdistinguished from "oily liquid", i.e. a fuel, petroleum or coaltarhydrocarbon oils and the like, which do not effect a change in color ofthe composition of the present invention. The aqueous liquids referredto hereinabove may contain up to about 95% of oxygenated hydrocarbon andare typically obtainable from the use of oxygenated blending componentsin hydrocarbons, such as gasoline, which are leached from thehydrocarbon into the water layer.

The indicator dyes employed in the composition of the present inventionare water-soluble dyes which are readily available from commercialsources as fine anhydrous crystalline powders. In general, the dyeparticles exhibit diameters not greater than about 200 microns. Thesedyes are characterized as being capable, upon contact with water, ofeffecting color change of the paste composition in the pH range betweenabout 7 and about 11, preferably between about 8 and about 10. Such dyesare normally employed as components of paste compositions in an amountsufficient to provide the desired color change. In general, such dyesmay be employed in concentrations ranging from between about 1 and about10, preferably between about 4 and about 8 percent, based on the totalweight of the paste composition. Representative indicator dyesemployable as constituents in the compositions of the invention include:phenolphthalein, o-cresolphthalein, p-naphtholbenzein, ethylbis(2,4-dinitrophenol) acetate, thymolphthalein, and Nile Blue A(CI51180), it being understood that any dye meeting the aforementionedspecifications is employable in the compositions of the invention. Ifdesired, admixtures of these indicator dyes may be employed in amountsranging from about 1:10 to 10:1, by weight, to achieve a high contrastof color change when the paste composition is employed in an environmentrequiring an especially high contrasting change, e.g. in storage tankscontaining excessive quantities of dirt, rust or other dark coloredmaterials or debris.

The caustic powder employed as a constituent of the visual indicatorpaste compositions of the present invention must be one which does notdissolve and ionize in the liquid carrier, but is readibly soluble inwater. In general, anhydrous solid forms of an alkaline earth oxide,hydroxide, or mixtures thereof, or any compound which will generate analkaline earth oxide or hydroxide in situ, e.g. an alkaline earthhydride, are suitable for use in such compositions. These materials maybe in the form of a finely divided technical grade crystalline powderand are readily available from commercial sources. Typical causticpowders employable in accordance with the invention include calciumoxide, calcium hydroxide, strontium oxide, strontium hydroxide, bariumoxide, barium hydroxide, magnesium oxide, magnesium hydroxide, andhydrides of these metals such as calcium hydride. In general, thecaustic powder is employed in a concentration ranging from about 1 toabout 25 percent, preferably between about 5 and about 20 percent, byweight of the composition, in order to provide the desirable watersensitivity properties characteristic of the compositions of the presentinvention.

As a vehicle for the paste composition of the invention, there isemployed a liquid carrier which is capable of absorbing water, but isnot readily leached by water or by the hydrocarbon. Any organiccompound, or mixture thereof, exhibiting such characteristics and whichis inert to the other composition ingredients may be employed. Otherrequired characteristics of the vehicle are that it be characterized bya sufficiently high viscosity for good paste consistency, have a lowfreezing point and not inhibit fairly rapid, i.e., within about 2minutes or less, color reaction of the indicator dye, upon contact ofthe composition with aqueous solutions. Especially suitable liquidcarriers employable include aliphatic polyols, alkylene glycols andpolyalkylene glycols of sufficiently high molecular weight to precludetheir solubility in the water/hydrocarbon environment in which thevisual indicating paste composition is employed. In general, the polyolsand glycols, or mixtures thereof, having a molecular weight of at leastabout 75 are useful as liquid carriers in the composition of the presentinvention. Illustrative polyols employable in the composition of theinvention include 1,4-butanediol; 1,3-butanediol; hexylene glycol;1,2,6-hexanetriol; and 1,6-hexanediol. The polyalkylene glycols normallycontain from between about 2 and 4 carbon atoms in each alkylene chainunit of the polyalkylene glycol. Illustrative polyalkylene glycolsemployable include polyethylene glycol, polypropylene glycol, andpolybutylene glycol having molecular weights between about 200 and about4000. As is evident to those skilled in the art, such polyols andglycols are commercially available products and are employable eitheralone or as mixtures with or without other conventional liquid carriers,and, when employed as mixtures, are employed to obtain the optimumhydrophilic/hydrophobic balance. In general, the liquid carrier isemployed in an amount of at least about 40 percent, and generallybetween about 50 and about 90 percent, based on the weight of the pastecomposition. Polyalkylene glycols of molecular weight between about 200and 1500, employed in an amount of between about 60 and 80 percent ofthe total weight of the paste composition, provide particularlydesirable properties, and hence, are preferred for use in thecomposition of the invention.

If desired, a gelling agent which serves as a thickner and/or colorstabilizer, and which is inert to the ingredients of the composition,may optionally be employed as an added constituent of the pastecomposition of the invention. The purpose of use of such gelling agentis to retard leaching and to gel the composition. Any known fillerhaving a color other than that which would interfere with the visualdetection provided by the paste composition of the invention in itsapplication and which serves to provide the thickening properties andcolor stabilization indicated may be employed. Illustrative suitablegelling agents employed as components of the composition of the presentinvention include inert filler or diluents such as talc, clay,diatomaceous earth, calcium silicate, silica, fumed colloidal silica,alumina, pyrophyllite, calcite, or mixtures of the same or other finelydivided solid materials. In general, if employed the gelling agent isused in quantities up to about 20 percent, or more, preferably betweenabout 5 and about 15 percent, based on the total weight of the pastecomposition.

The compositions of the present invention may be prepared by customarymethods employed in the art for the production of paste compositions. Ingeneral, the components of the composition are conventionally fed to amixer at ambient temperature and blended to an even, smooth paste, itbeing understood that blending at elevated temperatures or under otherconditions conventionally employed for blending pastes may be employed.Incorporation of the ingredients of the composition is readily effectedby incorporation of the solid components, individually or together, bygrinding, dry-mixing, or blending into the vehicle. Hence, the insolublebase, indicater dye, boron compound and/or gelling agent, if employed,may be incorporated prior to, concurrently with, or after theincorporation of the other solid ingredients in the vehicle.Alternatively, prior to incorporation of the solid ingredients in thevehicle, the boron compound preferably is dissolved in the vehicle.Since these boron compounds and their hydrolysis products are soluble inthe vehicle, these compounds are ideal for drying the vehicle beforepreparation of the paste and thereafter the boron compound continues tofunction as a water scavenger during storage and use of the paste.

It is to be understood that the paste composition of the presentinvention may additionally include adjuvants well-known to those skilledin the art, such as sticking agents, and the like. Hence as stickingagents, there may be employed materials such as casing gelatine,cellulose derivatives such as carboxy-methyl cellulose, sulfite wasteliquor, water-dispersable synthetic resins, mineral oil, or equivalentadhesives, all of which are well-known in the art.

The present invention provides readily utilizable stabilized pastecompositions which are particularly adapted for locating the water levelin tanks or other storage or delivery facilities for hydrocarbons whichmay be admixed with water, or with "aqueous liquids", as above defined.A particular application of the compositions of the present invention isfound in measuring the level of water bottoms in gasoline storage tankswhich must be monitored frequently to prevent the delivery of water intovehicle gasoline tanks. Although presently available paste compositionsare generally satisfactory for detection of levels of water in tanks;however, water bottoms of storage or delivery facilities for gasolinecontaining oxygenated blending components, i.e. gasolines containingalcohols or ethers such as methanol, ethanol, tertiary butyl alcohol,methyltertiary butyl ether, or mixtures thereof, may contain up to about90 volume percent of alcohol in the water level.

The invention may be more fully understood by reference to the followingexamples:

DESCRIPTION OF THE PREFERRED EMBODIMENTS EXAMPLE I

A paste composition comprised of the components indicated in Table Ibelow was prepared:

                  TABLE I                                                         ______________________________________                                        Component         Weight Percent                                              ______________________________________                                        Phenolphthalein   7.3                                                         Calcium Oxide     20.0                                                        Tripropylene Glycol*                                                                            65.9                                                        Fumed Colloidal Silica                                                                          6.8                                                                           100.0                                                       ______________________________________                                         *containing 1.0 weight percent tripropyl borate                          

The components were fed to a mixer at ambient temperature and blended toa even, smooth colorless paste. Thereafter, the lower end, approximately4 inches, of a conventionally employed measuring tank gauge was coatedwith a thin layer of the paste and the probe was lowered to the bottomof a gasoline tank containing unleaded gasoline motor fuel, blended withOXINOL® 50 blending component comprised of methanol and tertiary butylalcohol. After holding the gauge to the bottom of the tank forapproximately 10 seconds, the gauge was removed from the tank and therewas observed a deep red color on the end of the probe showing the depthof the water/alcohol layer.

EXAMPLE II

A paste composition comprised of the components indicated in Table II,below, was prepared:

                  TABLE II                                                        ______________________________________                                        Component         Weight Percent                                              ______________________________________                                        Thymolphthalein   1.4                                                         Calcium Oxide     21.3                                                        Tripropylene Glycol*                                                                            70.0                                                        Fumed Colloidal Silica                                                                          7.3                                                         ______________________________________                                         *containing 1.0 weight percent tripropyl borate                          

The components were fed to a mixer at ambient temperature and blended toa even, smooth colorless paste. Thereafter, the lower end, approximately4 inches, of a conventionally employed measuring tank gauge was coatedwith a thin layer of the paste and the probe was lowered to the bottomof a gasoline tank containing unleaded gasoline motor fuel, blended withOXINOL® 50 blending component comprised of methanol and tertiary butylalcohol. After holding the gauge to the bottom of the tank forapproximately 10 seconds, the gauge was removed from the tank and therewas observed a deep blue color on the end of the probe showing the depthof the water/alcohol layer.

EXAMPLE III A paste composition comprised of the components indicated inTable III below is prepared:

                  TABLE III                                                       ______________________________________                                        Component          Weight Percent                                             ______________________________________                                        Phenolphthalein    9.6                                                        Thymolphthalein    1.9                                                        Calcium Oxide      19.2                                                       Polypropylene Glycol 725*                                                                        62.8                                                       Fumed Colloidal Silica                                                                           6.5                                                        ______________________________________                                         *containing 0.5 weight percent tripropyl borate                          

The components were fed to a mixer at ambient temperature and blended toa even, smooth colorless paste. Thereafter, the lower end, approximately4 inches, of a conventionally employed measuring tank gauge was coatedwith a thin layer of the paste and the probe was lowered to the bottomof a gasoline tank containing unleaded gasoline motor fuel, blended withOXINOL® 50 blending component comprised of methanol and tertiary butylalcohol. After holding the gauge to the bottom of the tank forapproximately 10 seconds, the gauge was removed from the tank and therewas observed a deep purple color on the end of the probe showing thedepth of the water/alcohol layer.

EXAMPLE IV Comparative Example

In order to test the stability of the borate containing paste versus thenon-inhibited paste, a relative test was developed.

The test employs a constant humidity chamber comprised of a largedessicator with an aqueous slurry of calcium chloride in the lower base.At room temperature the humidity of the enclosed air space remainsconstant at 33 relative percent. The upper section of the dissicator isseparated from the aqueous solution by a shelf having many openings forfree circulation of the humidified air. The paste compositions employedin this Comparative Example are identified in Table IV, below:

                  TABLE IV                                                        ______________________________________                                                        Weight Percent                                                                  Inhibited                                                                              Noninhibited                                       Component         Paste    Paste                                              ______________________________________                                        Phenophthalein    5.7      5.7                                                Calcium Oxide     9.0      9.0                                                PolyPropylene Glycol 725                                                                        46.65    47.5                                               PolyEthylene Glycol 400                                                                         28.3     28.3                                               Tripropyl Borate  0.85     --                                                 Fumed Colloidal Silica                                                                          9.5      9.5                                                                  100.0    100.0                                              ______________________________________                                    

Samples of paste are prepared on microscope slides by placing a smallamount of paste on the surface and covering with a circular cover glass.The cover glass is pressed down firmly to spread out evenly the pastefilm to the edges of the cover glass. The slide is then placed insidethe dessicator. In this manner, samples of various paste compositionsmay be made at the same time for comparative measurement.

Periodically, observations are made of any color changes that may occurdue to water absorption from the humidified air. Usually the outermostedge of the inhibited paste will begin to color within the first hour.Thereafter, the progress of color development into the interior takesincreasingly longer times. Arbitrarily, the point for comparison istaken as the time required to color the first 0.5 millimeter of thepaste film as measured from the leading edge. For the noninhibited paste(i.e. paste devoid of boron compound) the time for 0.5 mm coloration at75° F. was 6 hours. In contrast, paste inhibited with tripropyl boraterequired a residence time of 150 hours to reach the same degree ofcoloration.

While the invention has been illustrated and described and is consideredto be the most practical and preferred embodiments, it is recognizedthat many variations are possible and come within the scope thereof.

I claim:
 1. A method for detecting water present an an ingredient in anadmixture of an aqueous solution and a separate hydrocarbon liquid phasecomprising:(a) providing a water finding probe coated on at least oneend thereof with a visual indicating paste composition comprising (i) awater soluble indicator dye capable of changing color in the pH rangebetween about 7 and 11, (ii) an inorganic base in the form of a causticpowder dispersed in a liquid carrier capable of absorbing water butwhich is not rapidly leached by water or hydrocarbon, (iii) a gellingagent, and (iv) a boron-containing compound which is miscible with orsoluble in said carrier and capable of being hydrolyzed upon contactwith water to yield boric acid or a salt thereof, present in a moistureinhibiting amount, (b) inserting the coated end of said probe into saidadmixture, and (c) removing said probe from said admixture, andobserving thereon, a clear detectable color change, without bleeding orrun-off, upon contact with the aqueous solution contained in saidadmixture.
 2. The method of claim 1 wherein said base is, a memberselected from the group consisting of an oxide and a hydroxide of analkaline earth metal.
 3. The method of claim 2 wherein said liquidcarrier comprises at least one polyalkylene glycol.
 4. The method ofclaim 3 wherein said base is finely divided solid calcium oxide.
 5. Themethod of claim 4 wherein said indicator dye is a member selected fromthe group consisting of phenolphthalein, o-cresolphthalein,p-naphtholbenzein, ethyl bis(2,4-dinitrophenol) acetate,thymolphthalein, and Nile Blue A (CI51180).
 6. The method of claim 5wherein the the boron-containing compound is a boron ester.
 7. Themethod of claim 6 wherein said boron ester is a straight chain trialkylborate.
 8. The method of claim 7 wherein said boron-containing compoundis present in an amount of between about 0.5 and about 5%, by weight ofthe composition.
 9. The method of claim 1 wherein said indicator dye isphenolphthalein, said liquid carrier is a polyalkylene glycol whichcontains two to four carbon atoms in each unit of the alkylene chain andhas a molecular weight of between about 200 and 1500, said gelling agentis fumed colloidal silica and said boron containing compound istripropyl borate present in an amount of between 0.5 and about 3% of thevisual indicating paste composition.
 10. The method of claim 1 whereinthe aqueous solution contains not greater than 95% of an oxygenatedhydrocarbon.